textproduct: Albany

WHAT HAS CHANGED

Forecast snowfall amounts for this afternoon into tonight have decreased near the I-90 corridor (mainly under an inch, with some areas just receiving a coating). This also has necessitated cancellation of previous Winter Weather Advisory for Berkshire and eastern Rensselaer Counties.

Confidence in wind gusts reaching 45-50 mph has increased within the Mohawk Valley, Capital Region and Berkshires for late tonight through Wednesday morning, where a Wind Advisory has been issued.

Trends continue to shift southward and colder for Friday- Saturday system, favoring mainly snow with potential impacts primarily near and south of I-90.

KEY MESSAGES

1. Locally slippery travel conditions this afternoon into tonight, mainly across the SW Adirondacks and higher terrain in southern VT where snow gradually tapers to snow showers overnight. Some patchy freezing drizzle may also occur in these areas this evening.

2. Strong gusty west/northwest winds develop late tonight and persist through Wednesday morning, with gusts reaching 40-50 mph within portions of the Mohawk Valley, eastern Catskills, Berkshires and central/northern Taconics.

3. Trends continue to favor a track farther south with Friday- Saturday system, with mainly snow expected and greatest chances for impactful snowfall mainly near and south of I-90.

4. Precipitation develops Sunday and may continue into Monday morning, most likely beginning as snow or a wintry mix (including freezing rain) before potentially ending as plain rain.

DISCUSSION

KEY MESSAGE 1...

Ongoing system bring 2 main areas of snow, with initial area mainly across SE Catskills, mid Hudson Valley and NW CT tapering off over the next 1-2 hours. Any additional snow accumulations in this area should remain under an inch. Meanwhile, areal coverage of snowfall now increasing across the southern Adirondacks and southern VT where isentropic lift is increasing along with approach of left exit region of upper level jet. This area will continue to see periods of light to moderate snow through this afternoon before gradually tapering off this evening. In between these 2 areas near the I-90 corridor, although periods of light snow will persist through mid afternoon, snowfall intensity should remain light and with borderline temps around/just over freezing, any additional accumulations should generally remain below an inch. Northern areas should see an additional 1-3 inches except 3-4 inches across the SW Adirondacks and higher terrain areas of southern VT, where snow will linger into this evening before tapering to snow showers overnight.

As mid level dry slot moves in from the west, ice nuclei should decrease and may allow for patchy drizzle/freezing drizzle across portions of the southern Adirondacks/southern VT this evening, with isolated/scattered rain showers elsewhere, before changing back to snow showers as colder air aloft moves back south and east.

KEY MESSAGE 2...

Gusty west/northwest winds in the wake of a shortwave and occluded frontal passage should develop after midnight tonight and persist through late Wednesday morning. Channeling of winds within the Mohawk Valley, Capital Region and Berkshires should allow for some gusts to reach 40-50 mph, with wind gusts elsewhere mainly 35-45 mph. Winds will gradually decrease Wednesday afternoon/evening from these magnitudes.

KEY MESSAGE 3...

Increasingly confluent upper level flow across eastern Canada will allow high pressure to build southward into the region Thursday into Friday. Another low pressure system is expected to track east-southeast from the Great Lakes region. Latest model trends are now favoring areas mainly south of I-90 for accumulating snowfall, with 13Z/NBM 24-hour probs for >2" snowfall ending 7 AM Sat at 60-80% south of I-90, with similar probs for >6" snowfall at 30-50% in these same areas. With a track farther south, potential for wintry mix for this period has decreased from previous forecasts, however will have to watch future trends in case track shifts back slightly northward once again.

KEY MESSAGE 4...

System for Sunday-Monday looks slightly warmer aloft, however lingering cold/dry low-level air may allow for precipitation to begin as sleet/freezing rain to at least portions of the region, with best chances for areas near and north of I-90. There still remains considerable uncertainty with this system, particularly the track and evolution of precipitation types across the region, however 24-hour probs for liquid equivalent amts through 7 AM Monday are 40-60%, suggesting areas of moderate precipitation are quite possible.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Light snow or light mix of rain and snow showers continue to move from west to east the start of this TAF period. Ceilings continue to range between IFR/MVFR conditions through about 5z when ceilings gradually go to a mix of MVFR/VFR conditions. Winds change direction overnight from southerly to northwesterly and increase after 5z to between 10 and 20 knots. Wind gusts continue to increase after 5z for KPSF and KALB, ranging between 35 and 45 knots between 10z and 14z before decreasing to between 25 and 35 knots. Low level wind shear at 2 kft between 10z and 14z could reach up to 50 knots for KALB to KPSF. FOr KPOU and KGFL, LLWS could reach between 35 and 40 knots for the same timeframe. For KGFL, they could be sheltered from the strongest winds with gusts only ranging between 10 and 20 knots through the end of the TAF period.

Outlook...

Wednesday Night: Moderate Operational Impact. Chance of SHSN. Christmas Day: Moderate Operational Impact. Breezy. Chance of SHRA...SHSN. Thursday Night: Low Operational Impact. Breezy. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SN. Friday Night: High Operational Impact. Definite SN. Saturday: Moderate Operational Impact. Chance of SN. Saturday Night: Moderate Operational Impact. Chance of SN...FZRA. Sunday: High Operational Impact. Definite RA...FZRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Wind Advisory from 3 AM to noon EST Wednesday for NYZ038>040- 047>054-058>061. Winter Weather Advisory until 7 AM EST Wednesday for NYZ032- 033-038-039-082. Winter Weather Advisory until 5 PM EST this afternoon for NYZ063. MA...Wind Advisory from 3 AM to noon EST Wednesday for MAZ001-025. VT...Winter Weather Advisory until 7 AM EST Wednesday for VTZ013- 014.